Simple

blockly.xml

<xml xmlns="https://developers.google.com/blockly/xml"><block type="BaseContractType" id="root_contract" deletable="false" x="13" y="187"><statement name="BaseContractType"><block type="WhenContractType" id="1$^G-OM+X4CanW*|DYCy"><field name="timeout">10</field><statement name="case"><block type="DepositActionType" id="euJ@CL!I+}FI#_XZ+l@M"><value name="from_party"><block type="RolePartyType" id="NgyPP@kP;niOIVce:Zc#"><field name="role">donor</field></block></value><value name="value"><block type="ConstantValueType" id="#1b#CAIVfD!,0:;h%:9p"><field name="constant">1000</field></block></value><value name="token"><block type="AdaTokenType" id="PBo!tksEMb{cQSfcRMv1"/></value><value name="party"><block type="RolePartyType" id="SG?YM{^2{m]F/l,jpJ3="><field name="role">recipient</field></block></value><statement name="contract"><block type="PayContractType" id="G:PK|RMy_Mw4g.7Q#B8@"><value name="payee"><block type="PartyPayeeType" id="`E5z:`c;N!7,]uRsj%`X"><value name="party"><block type="RolePartyType" id="!Hbkm`-GFYGMFHL8}1Tv"><field name="role">donor</field></block></value></block></value><value name="value"><block type="ConstantValueType" id="Rk7-QOz-92z6{I7^YhX/"><field name="constant">900</field></block></value><value name="token"><block type="AdaTokenType" id="WlCTG^=mjqEpwV.Q+h%B"/></value><value name="party"><block type="RolePartyType" id="hPeGXN!k]1w[=y$#[)aJ"><field name="role">recipient</field></block></value><statement name="contract"><block type="CloseContractType" id="/pe|]Gym+]JhRv.W)~~!"/></statement></block></statement></block></statement><statement name="contract"><block type="CloseContractType" id="ih|ZUq*Af1AN)cIi]v.q"/></statement></block></statement></block></xml>

playground.marlowe

When
    [Case
        (Deposit
            (Role "recipient")
            (Role "donor")
            (Token "" "")
            (Constant 1000)
        )
        (Pay
            (Role "recipient")
            (Party (Role "donor"))
            (Token "" "")
            (Constant 900)
            Close 
        )]
    10 Close 

playground.marlowe.json

{}